Road grading machine



March 16, 1937.

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March 16, 1937. 1 s BURNS 2,074,081

ROAD GRADING MACHINE Filed Oct. 30, 1954 4 Sheets-Sheet 2 March 16, 1937. 1 s BURNS ROAD GRADING MACHINE 4 Sheets-Sheet 3 Filed oct. so, 1954 FIG'. 5.

Ztorayey Marh 16, 1937. 4 5, BURNS 2,074,081

ROAD GRADING MACHINE v Filed ost. 5o, 1934 4 sheen-Sheet 4 FIG4.

is i toryey Patented Mar. 16, 1937VV PATENT CFFICE.

ROAD GRADING MACHINE John Stephen Burns, Westminster, London, England ApplicationOctober 30, 1934:,` Serial No. 750,693 In Great Britain November 30, 1933 14 Claims.

This invention relates to grading machines with more especial reference to road graders for making earth or gravel roads in which a blade is adjustably mounted on a steerable vehicle so as to be capable of cutting the soil and imparting the desired profile to the surface traversed or passed by the machine.

In machines of this character as hitherto constructed, the plough frame has been of general A shape with its apex attached to the front of the grader-usually the king bolt or steering headand mounting at its rear the draft circle, plough circle, plough arms, mould board and blade,` the position of theV plough frame being controlled through two gear boxes operating cranked rods with adjustable lifting links which fix the angle and in the vertical plane the effective depth of cut accomplished by the blade of the machine in operation and by another gear box operating a i o sliding arm with movable link in the lateral plane.

Side shifting or the-lateral movement of the plough frame with its components results in loss in the depth of cut and the positioning ofthe blade for side cuts is only effected with difficulty and vide an improved construction of grading 'ma' chine having an increased range of positions for the blade and wherein setting of the blade to any position within its range may be readily effected while the stresses contingent on use will be more 40 appropriately distributed and the wear on the parts minimized, the likelihood of ultimate fracture being correspondingly reduced. Further and favorable objects will appear from the following description. I In accordance with the present invention the plough frame mounting the circle to which the blade is attached is carried by a cone-like structure normally disposed in the longitudinal axis of the machine, such structure being movable about its apex for setting the plough blade to give the desired side shift, inclination, or depth of cut.

Preferably also the circular base of the conelike structure is universally pivoted to the main frame, the structure being arranged With its virtual apex at the anchorage of the draw bar byy with consequent alteration in the depth of out,l

which the plough frame is drawn, and provision being made by means of appropriate gear boxes and screw-threaded stems for lateral and/or vertical bodily movement of the circular base of the cone in relation to the main frame to alter 5 theset of the blade.

The plough frame land draft circle,v about which the plough circle mounting the blade is adjustable in theusual manner, is mounted on an annular rim encircling the circular base of the cone and movable thereabout to set the blade to the desired inclination of cut, this assemblygiving a range of adjustment for the blade from a cutting position occupying the vertical at one side of the machine to a similar position at the other side.

Particular advantage accrues from the use of the circular or cone-like structure as a mounting for the plough frame, since all movements. thereof whether vertical for'setting the depth ofv cut, lateral according to the extent of side cut required or inclination to give the desired prof-lle, can each be had quite independently of the others, in contradistinction to existing arrangements of grader where, owing to the adjustments being effected through link and lever mechanism, any adjustment in the vertical direction modifies the lateral set of the blade as a matter of course and vice versa.

\ Wherever possible, it is desired to use irreversible screw-threaded stems actuated by gear boxes to produce movements of the parts within the range of permissible positions for the blade, since this method of actuation prevents unnecessary transmission of stress and permits of the control shafts being taken to the platform from the respective gear boxes. as light flexible cables, or telescopic rodding and universal couplers.

A further aspect of the invention resides in the provision of a front axle steerable about a central pillar'V pivotally connected to the frame of the vehicle so as to permit movement of the axle in the longitudinal plane, compression springs or other cushioning devices maintaining the central pillar or cushioning head in its normal position.

l Longitudinal exibility is thereby obtained and the likelihood of machines being damaged or deteriorated when traversing uneven surfaces is avoided.

` kThe invention will be further described with reference to the Vaccompanying explanatory drawings which illustrate one embodiment thereof, and in which,-

Fig. 1 `is a longitudinal view of the grader partly insection showing the controls, Fig. 2 .55

CTI

being a plan of the grader shown in Fig. 1 also partly in section, the operators platform and control mechanism having been removed more clearly to show the mechanism for adjusting the lean or rake of the rear wheels.

Fig. 3 is a front elevation partly in section and with the draw gear removed, and Fig. 4 is a rear View showing the operators platform and the hand and foot wheels by which the position of the plough blade may be adjusted at will.

Referring now to the drawings, but first more especially to the front carriage illustrated in Figs. 1, 2 and 3, a rigid front axle Iof general H-section is carried in a slotted tubular steering column 2, rotation of which, for steering the grader to follow its tractor, takes place about a vertical pin 3 depending from a platform 4, itself pivotal in a vertical plane about a transverse pin 5 borne in bracket castings 6 secured at the front end of the main frame constituted by longitudinal girders 1 and 8.

In contradistinction to the semi-rigidly mounted front carriages hitherto employed in machines of this character, the embodiment of grader illustrated employs a flexible front carriage relieving the grader frame of bending moment when traversing uneven surfaces, the central steering column 2 carried by the platform 4 being permitted movement in the vertical longitudinal plane of the grader about the transverse pin 5 against appropriate resistances shown as helical springs 9 and ID by which the tubular column is normallyA retained in and returned to its vertical position relative to the frame.

Moreover, the rigid front axle I is pivoted for limited angular vertical movement in relation to the tubular column 2 on a cotter pin I 9, Whereby the front wheels readily accommodate themselves to transverse inequalities without subjecting the main frame of the grader to torsion.

A triangular draw bar assembly is provided for connecting the grader with its tractor, a draw stirrup I I equipped with the usual draft cushioning spring I2 being provided at the front of a bifurcated draw arm, of which one adjustable arm I3 linksthrough a collar 22 hereafter described-with the upper end of the tubular column 2, the other arm 4 passing horizontally to a collar I5 at the foot of the tubular column 2 in the vicinity of the front axle I, the flexible mounting of the front carriage permitting it automatically to follow the rise or fall of the tractor when passing over uneven ground and its stability being at all times assured by the aforementioned compression springs or other cushioning devices 9 and I0 which tend to return the tubular column to its normal Vertical position.

Steering thrusts are distributed from a sprocket or pulley I6 adjacent the front of the draw bar assembly to points in the vicinity of the ends of the front axle by floating and adjustable tie rods |1 and |8.

Associated with the sprocket or toothed pulley I6 is a worm and worm wheel irreversible gear box ||6 connected by a flexible shaft ||1 with a steering wheel |I8 located above the platform at the rear of the grader, rotation of the steering wheel ||8 altering the relative position of the front axle I and the tubular column 2 in relation to the main draw arms I3 and I4, whereby the operator may accurately steer the grader on a desired course in wake of its tractor.

The pin I 9 by which the front axle I is pivoted to the tubular column 2 is notched exteriorly of the tubular column 2 and is lockedin position by the upper edge of the collar I5 occupying the notches, the collar I5 being in turn secured against displacement, while being permitted say 60 angular movement, by a stirrup clip 20 which provides a bottom cover for the tubular column 2 and which has fingers 2| extending up the sides of said column and secured thereto by bolts.

The vertical steering pin 3 is locked in position in the inverted platform 4 by its head engaging the transverse bearing pin 5, while in the top of the tubular column 2 is welded in a head |02 with an upwardly projecting circular boss I 93 providing a seat fo-r a correspondingly circular recess in the aforementioned collar 22.

The collar 22 is provided with a similar upstanding circular boss 23 providing a seat for a recess in the inverted platform 4 and is furnished with a frontal lug 24 to which the draft arm I3 is pinned and is split or bifurcated to provide a pair of rearwardly directed jaws between which is positioned a bearing or plough draft collar 25 also encircling the steering pin 3, the bearing collar 25 mounting at its rear a horizontal pin 26 to which the draft arms 21 and 28 of the plough frame and the draft circle 29 are pivoted.

Reference will now be had also to Fig. 4 in describing the circular cone-like structure mounting the said plough frame and draft circle 29. Essentially such structure comprises a circular base 30 which is not only pivotal about the axis of a horizontal screw-threaded stem 3| mounted in a gear box 32, in'turn vrotatable in a plane at right-angles to the plane of the base 39 upon an inclined bracket 33 secured to the main frame members 1 and 8, but said circular base 38 is also movable laterally, vertically and to a limited degree in rotation by means of the aforementioned lateral screw-threaded stem 3| actuated through its gear box 32 and by approximately vertical screw-threaded stems 34 and 35 actuated by gear boxes 36 and 31 in the manner hereafter described.

The plough frame comprised of draft arms 21 and 28 and draft circle hereafter generally designated 29, about which is rotatable the plough circle 38 carrying the mould board 39 and blade |39, is furnished at each end of its transverse diameter with a pair of upstanding lugs 48 in which are pins 4| by which the draft circle 29 is connected to the draft arms 21 and 28 and to brackets 42 on an annular frame 43 surrounding and movable about the circular base 39.

The lower half of this annular frame or great circle 43 is furnished with internal gear teeth 44 with which teeth enmeshes a spurwheel 45 appropriately borne in the circular base 39, a flexible shaft |44 connecting the spur wheel 45 with an operating wheel |45 adjacent the platform.

Rotation of the wheel |45 imparts rotarymcvement to the great circle 43 about the circular base 30, and since the plough frame and draft circle 29 mounting the plough circle 38 and mould board 39 and blade |39 is carried by this great circle 43, there is a corresponding bodily movement of the plough frame and blade about the centre of the circular base 3U.

A similar wheel |46 is connected through a flexible shaft |41 to a spur wheel 43 borne in the draft circle of the plough frame and enmeshing with gear teeth 41 furnished for the purpose of rotating the plough circle 38.

Readily releasable pawls, not shown, or bolts |38, may engage the gear teeth of the circles 38 and 43 to x them in adjusted positions, and it will be understood that the angular set of the blade 39 may be modified at the will of the operator by movement of the wheel |45 without affecting the incidence of cut set by the wheel |46, movement of which latter similarly modies the incidence of the blade without affecting the angle of cut determined by the position of the annular frame or great circle 43.

As aforementioned, final adjustments in the set of the blade and depth of cut can be accurately made through the gear boxes 36 and 31 on the vertical stems 34 and 35 which, When moved in unison, produce a bodily movement of the circular base 30 but which are also independentlyV movable through hand Wheels |34, |35 connected respectively to the gear boxes 36, 31 by flexible shafts |36, |31.

When either the gear box 36 or the gear box 61 is actuated independently of the other, the set of the blade is altered owing to movement of the circular base 30 about the stationary gear box, and to permit of this independent movement of the stems 34 and 35 arcuate `guides 48 and 49 on the circular base 30 slidably mount yoke-shaped bearing blocks 50 and 5| at the ends of the respective stems 34 and 35, the guide blocksbeing rigidly or otherwise connected to the stems in such manner as to prevent them from turning.

To relieve the transverse stem 3| of bending moment, the gear boxes 36 and 31 are mounted on and secured to transverse guide members 52 and 53 located respectively in front of and behind the gear box 32 and slidable in transverse guideways therein in consonance with the movements imparted to the transverse stem 3|.

Bodily lateral movement of the circular base 30 by projection of the transverse stem 3| through its gear box 32 is had from a hand wheel |30 rotating a bevel wheel |3| through a flexible universal shaft |32, the bevel |3| enmeshing with the second bevel |33 appropriately borne in the cover of the gear box 32.

The internal construction of the gear boxes 32, 36 and 31 is similar, each including a nut engaging its respective screw-threaded stem 3|, 34 or 35, which nut is provided with suitable thrust bearings in the gear box and has secured to it or is formed integrally with a bevel wheel rotated from the respective hand Wheel by a corresponding bevel, which, in the case of the gear box 3|, is mounted on the shaft of the bevel Wheel |33, while in the case of the gear boxes 36 and 31 is clutched to the flexible shafts |36, |31 rotated by the respective hand Wheels |34, |35.

The draft circle of the plough frame 29 has three-point suspension, since, in addition to the brackets 40 on its transverse diameter, it has a frontbracket 54 which is shown adjustably borne on a screw-threaded spindle 55 mounted in a transom 56 bridgingthe draft girders 21 and 28 of the plough frame, a `small hand wheel 51 serving for the'adjustment of the stem 55 to alter the rake of theI draft circle of the plough frame 29.

'I'he draft gear also includes the usual cushioning spring 58 in rear of the pin 26, the girders 21 and 28 and the transom 56 forming a rigid triangular assembly universally connected to the steering pin 3.

Provision is also made for adjusting the rake of the wheels to suit the contour of the ground traversed, but in contradistinction to 'previous constructionsrof grader Where toothed racks have Vbeen employed for this purpose, it is preferred to employ screw-threaded stems which may readily be encased in dustproof covers, and which, moreover, effect an irreversible drive thereby preventing unnecessary transmission of stress to the operating gear. Y 1 Y f Referringmore particularly to the rear View of the machine shown in Fig. 4, it will Vbe seen that the rear axle designated 60, at each end of which the rear wheels 6| are mounted on stub axles 62 having bell-crank arms 63, is furnished on its` upper surface with a guideway 64 along which is slidable a nut member 65, this nut member carrying a pin 66 to which are connected links 61 in turn pivoted to the bell crank lever 63 of the stub axles mounting the rear Wheels.

Transverse movement of the nut member 65 from its normal central position in which the rear wheels are vertical is effected through a screw-threaded stem 68 carried above the axle in bearings 69, one end of the stem 68 projecting through its bearing 69 and mounting a bevel wheel 10 enmeshed With a corresponding bevel wheel 1| connected through a flexible shaft |10 with a hand wheel |1| Y ,Rotation of the hand wheel |1| thus imparts rotation to the screw-threaded stem 68 and causes bodily lateral movement of the nut member along the axle 60 movement of the nut acting through the links 61 and the bell crank arm 63 to impart the desired rake or lean to the rear wheel 6|.

Similar leaning Wheel mechanism is furnished for the front axle as clearly shown in Fig. 3, to

which mechanism the same reference numbers have been applied and the rake of the front wheels, designated 59, is set through independentl'y controlled gear for such front Wheels by a handle |58 and flexible shaft |59.

In some cases it may be desirable or convenient, e. g. to avoid the spoil from the blade |39, to offset the rear wheels 6| in relation to the frame of the grader, and the embodiment illustrated provides rear axle shifting mechanism to this end.

By reference to Figs. 1, 2 and 4, it Will be seen that the rear end of the grader frame is constructed as a platform 15 slung under the rear axle 60, which is slidable transversely in relation to the platform 15 in guideways formed by bearing blocks 16 and 11 in front of and behind the axle 60 and projecting over the lower webs thereof, a spacing block 18 being secured to the platform 15 and xing the relative distance between the opposed channel frames constituting the rear axle 60.

Secured in any appropriate manner, e. g. by bolts, to the front channel of the axle 60, is a bracket 19 including a nut 80 which rides on a screw-threaded stem 8| borne in thrust bearings on the grader frame and having keyed at one end a bevel Wheel 82.

Enmeshed with the bevel wheel 82 is a second bevel wheel 83 connected through a flexible shaft |82 to a hand Wheel |83, rotation of the hand wheel |83 thus imparting rotation to the screwthreaded stem 8| and thereby transversely shifting the nut 80 and with it the axle 60 in regard to the main frame or platform 15. l

It will be understood that the leaning wheel mechanism, being mounted directly on the axle 60 and being operated through a flexible shaft |10, is unaffected by bodily shift of the axle and vice versa, While since both shift and rake of the rear wheels are. effected through irreversible transmissions, i. e. screw-threadedstems,there is consequent self locking in any adjusted position.

The load operated against when reducing the lean of the wheels may be partially compensated by compression springs 88 which store energy on effecting lean and employ it when the action is reversed.

As is clearly shown in Figs. l and 2, the main frame is splayed in r-ear of the gear box 3D and is swept downwardly in front of the rear axle to the platform 15, the splayed portion carrying a suitable platform 84 of sheet metal for the operator or driver, over which platform the various control wheels are conveniently grouped, the wheels |45 and |46 controlling respectively the position of the annular frame or great circle 43 and of the plough circle 38 which are adjacent the upper surface of the platform being furnished with projecting spokes so as to be readily footoperated.

When moving the blade to any required position only light pressure is necessary on the hand wheels, and to assist in the bodily upward movement of the circular base 43|'l and plough frame by means of the large hand wheels |34, |35 operating the screw-threaded stems 34 and 35 through the gear boxes 36 and 31, a tension spring 85 may be disposed in the rectangular space between the frame members 1 and 8 and may be connected to the circular base 38 by a flexible link 86 running over a guide 81 so as to exert an upward pull on the plough frame counteracting the weight of the latter to some extent.

The transverse pin 5 mounting the front carriage is shown projecting at each side of the brackets 6 and thus provides a suitable anchorage for a scarifler where it is desired to employ the machine with such an implement.

The manifold advantages of the improved grader will be apparent to those skilled in the art, particularly advantageous features of the embodiment described being as follows:-

1. The three point suspension with floating front axle removes all running stresses from the grader frame, the whole front assembly being permitted movement in the longitudinal plane against the resistance of the spring cushions 3 and I0, while the front axle is pivoted on the pin I9 for limited Vertical angular movement in regard to the column 2.

2. Draw stresses are transmitted direct to the plough frame and draft circle 29 through the steering pin 3 in double shear, the collar 25 to which the draft girders 21 and 28 are connected being disposed between the two jaws of the collar 22. The main frame is thereby further relieved of stress.

3. All movements of the blade 39 originate from the common centre, i. e. the centreof the circular base and normally of the transverse stem 3| positioned in the central gear box, it being impossible for any two movements to conflict and jam.

4. All movements of the blade are independently controllable without inter-action, there being no loss of cut on side shift.

5. The common centre is itself movable in a rectangle limited only by the range of adjustment afforded by the lateral stem 3| and the vertical stems 34 and 35, the specific embodiment illustrated giving a rectangle 2 wide by 18" deep, although this can be varied.

6. In addition to bodily movement of the common centre angular movement of the blade |38 from a set position up to the Vertical at one side of the machine to a similar position at the other can be had through the revoluble annulus or great circle 43.

'7. Final adjustments in the set of the blade and depth of. cut can be accurately made on the vertical stems 34 and 35 by means of the hand wheels |34, |35.

8. The normal movement of the plough circle 38 enables the blade incidence to be varied at will, and also may be usefully employed to facilitate shifting of the blade for angular side cuts.

9. Wheel rake for both axles and lateral shift for the rear axle is obtained through screwthreaded stems by irreversible drive rendering wheels and axles self-locking in any adjusted position.

10. Standard gear boxes may be used throughout and may be operated from the platform through flexible cables, since self-locking transmissions are used with two exceptions (a) the plough circle, and (b) the great circle, both of which are readily locked with pivoted pawls.

11. Unnecessary transmission of stress in the controlling gear is avoided and the screwthreaded stems are relieved of substantially all bending moment.

It will be understood that in place of the rotating nuts in the gear boxes 32, 36, 31, the necessary movements of the circular base 30 could be had through gear boxes rotating the stems 3|, 34, 35 in stationary nuts. Moreover, where desired, the vertical stems 34, 35 can be relieved of transverse thrust or bending moment by jacks bridging their gear boxes 36 and 31 and the circular base 3U, or guides, similar to the guides 52 and 53, may be provided also for the gear boxes 36 and 31.

A flexible shaft may be connected to the stem 55 whose hand wheel 51 can then be positioned adjacent the platform, whereby all movements of the blade can be effected without the operator having to dismount from his platform.

It will also be understood that while the embodiment of grader illustrated is adapted to be towed by a suitable tractor, the invention is also applicable to self-propelled vehicles or maintainers, in which case the floating front axle assembly would be replaced by a rigid axle equipped with steerable wheels and the draft girders 21, 28 would be pivoted directly to the frame of the grader near its front end instead of to the steering pin.

What I claim is:-

1. In a grading machine, a main frame mounted on wheels, a ring member mounted on and encircling the main frame, a plough frame with mould board and blade suspended from, said member, means for revolving said member with the plough frame about the main frame and means for moving the centre of revolution of said member relatively to the main frame.

2. A grading machine including a main frame mounted on wheels, a member mounted 0n and encircling the main frame, a plough frame with mould board and blade suspended from said member, means for revolving said member about the main frame and means for moving it vertically in regard thereto, whereby to position the blade.

3. A grading machine including a main frame mounted on wheels, a member mounted on and encircling the main frame, a plough frame with `mould board and blade suspended from said member, means for revolving said member about the main frame, means for moving it vertically and means for moving it laterally in regard thereto, whereby to position the blade. Y

4. A grading machine including a main frame mounted on wheels, a member mounted on and encircling the main frame, a plough frame with.

mould board and blade suspended from said member, guide Vmeans for transmitting stress from said member to the main frame, means separate therefrom for moving said member laterally in regard to the frame, means for moving it vertically in regard thereto, and means for revolving it about the main frame.

5. A grading machine including a main frame mounted on wheels, a circular member mounted about the middle of said main frame and encircling same, a plough frame suspended from said member, means for effecting revoluble movement of said member in regard to said main frame and means for effecting independent vertical and transverse movement thereof whereby all movements of the blade are independently controllable without inter-action.

6. In a grading machine, a. main frame mounted on wheels, a circular structure mounted on and encircling the main frame, means for bodily moving said structure relatively to the main frame, an annular member revolubly mounted on said structure and spaced from said main frame, a plough frame with mould board and blade suspended from said member and means for revolving said member with the plough frame about" the main frame.

'7. A grading machine including a main frame mounted on wheels, a circular structure located approximately midway of the frame and encircling same, means for effecting vertical movement of the structure and means for effecting transverse movement of the structure, an annular member revolubly mounted on said structure, a plough frame suspended from said mem-V ber and means for revolving said member about the structure.

8. In a gradingmachine, a main frame mounted on wheels, a steerable fore carriage to said main frame, a plough frame with mould board and blade, draft arms on said plough frame coupling it with said fore carriage, and means for suspending said plough frame from the main frame and for moving it vertically, laterally and revolubly in regard thereto, including a ring member, brackets on said ring member to which said plough frame is directly pivoted the ring membernbeing spaced from but revolubly and movably mounted on and encircling the main frame. l

9. A grading machine according to claim 7, wherein the means for effecting revoluble movement of said member comprises a spur wheel mounted on said circular structure and enmeshed with gear teeth furnished on said member, and a flexible shaft connecting the spur wheel with an operating device.

10. A grading machine including a main frame mounted on wheels, an operators platform to said main frame, a steerable fore carriage to said main frame, a member mounted on and encircling the main frame, a draft circle suspended from said member, a plough circle with mould board and blade carried by said draft circle, draft arms coupling said draft circle with said fore carriage, means for angularly setting the plough circle relative to the draft circle, means for revolving said member about the main frame, means for moving it vertically and means for moving it laterally in regard thereto, said means all being operable from said platform whereb to position the blade.

11. In a grading machine, a main frame mounted of wheels, a circular structure mounted v on and encircling the main frame, means for moving said structure to and from the axis of the frame, guide means carried by said structure for transmitting stress from it to the main frame, an annular member revolubly mounted on said structure, a plough frame with mould board and blade suspended from said member and means for revolving said member with the plough frame about the main frame.

l2. In a grading machine, a main frame mounted on wheels, a circular structure located approximately midway of the frame and encircling same, means for mounting the structure on the main frame including lateral and vertical screw stems and gear boxes for moving said structure laterally and vertically, guide means slidably connecting said structure with said stems for transmitting stress from said structure to the main frame, an annular member rotatably mounted on said structure,v a plough frame suspended from said member and means for revolving said member about the structure.

13. A grading machine according to claim 12, whereinv the means for mounting the circular structure on the main frame comprises a bearing furnished on the main frame approximately midway between the front and rear wheel axles, a gear box carried by said bearing and mounting a transverse screw-threaded stem, secondary gear boxes at each end of said stem mounting approximately vertical screw threaded stems providing a four-point carriage for the circular structure and transverse guide members engaged in said gear boxes to relieve the transverse stem of bending moment, said structure being moved laterally by operation of the gear box for the transverse stem and vertically by operation of the secondary gear boxes for the vertical stems respectively to modify the lateral disposition of the plough blade and its depth of cut.

14. A grading machine according to claim 12, wherein the means for mounting the circular structure on the main frame comprises a bearing furnished on the main frame approximately midway between the front and rear wheel axles, a gear box carried by said bearing and mounting a transverse screwthreaded stern, secondary gear boxes at each end of said stem mounting approximately vertical screwthreaded stems having at each end yoke-shaped bearing blocks engaging arcuate guide blocks of said structure, the bearing blocks being connected to the Stems in such manner as to prevent them from turning, and transverse guide members engaged in said gear boxes `to relieve the transverse stem of bending moment, said structure being movable laterally by operation of the gear box for the transverse stem, vertically by operation to equal extents and in like manner of the two secondary gear boxes for the vertical stems, and to a limited degree in rotation by operation to unequal extents or in opposite manner of said secondary gear boxes, whereby to set the position of the plough blade.

JOHN S. BURNS. 

